Computer Configuration for Developing in Unreal. Anyone can give me advices?

Hi, Everybody! I am a programmer in game industry. Recently I focused on Unreal 4 development. I want to buy a desktop for developing in Unreal Engine. But I am not sure about the hardware configurations. So can anyone give me some advice? I have some questions:
Mainboard. I have to decide to use a X570 chipset since it supports PCIe 4.0 data transfer.

  1. About the CPU. Sould I use Ryzen 3700X or 3900X? Programmer can tolerate 3700X? Or 3700X is enough? Is there any necessity to use 3900X? If I use 3700X CPU for compiling the whold project, will it be too slowly, and 3900X will be much faster?
  2. About the GPU. Since the NVIDIA RTX 30XX is about to shipping several days later. I plan to buy a second hand GTX970 for use temporarily. Later will transfer to RTX30XX(3070 or 3080). If I want to develop some real-time ray-tracing application. Should I transfer to RTX 30XX or RTX 20XX, or just GTX 16XX is enough? And the speed for different GPU matters?
  3. About the Storage. Epic recommend SSD storage. So may I use SATA SSD storage with a 6Gb/s transfer speed or higher? Does the seed of SSD matters too much?
    I am williing to receive your answers. Thank you very much!

For Quad-Channel RAM memory bandwidth you might want to consider a Ryzen Threadripper 2920X or 3960X CPU for AMD. Otherwise for Intel LGA2066 with Quad-Channel RAM support there is the i9-10920X CPU.
Install at least 32GB RAM better yet having 64GB.
For the GPU I wouldn’t waste time and money with a GTX 970. You can get a used GTX 1060 3GB or 6GB at very cheap prices which is faster than the 970. But buying a RTX 3060Ti or plain RTX 3060 would be the best bet as soon as it gets released.
SATA SSD would be enough for most tasks or you could get NVMe SSD. Anyway for maximum performance and reliability I would get a used hardware Adaptec/Microsemi RAID SAS controller that can be bought at cheap prices on eBay. A 71605 or 7805 model then you could add 4 , 6 or 8 500GB Sandisk SSD and you could configure them with RAID-5 or RAID-6 protection.
Also ensure to buy a good UPS like the APC ones.

**To DarkS474: **Thank you! Since my budget is limited(because I have to use my own $$$). so Ryzen Threadripper is a bit expensive for me. Before I used to aim at Ryzen 3900X, but AMD will ship its Zen3 CPU next month…It is hard to make the decision waiting for Zen3 or just buy a cheap 3700X now. From your reply, it seems that more CPU cores are better, so Ryzen 3700X are not fast enough(I am not sure about this)? GTX 970 is just for short time usage, because i want to buy the computer next week, and i can’t get RTX 3070 or RTX 3080 before November(they said that there are not so many products supplied in the beginning and the price also not stable)

what do you think the following choices?

  1. Ryzen 3700X + X570 chipset motherboard + 32G DDR4 3200 DRAM + RTX 3070 or RTX 2070s
  2. Ryzen 3900X + X570 chipset motherboard + 32G DDR4 3200 DRAM + RTX 3070 or RTX 3080.
  3. Ryzen 4000 series(Zen3) + X570 chipset motherboard + 32G DDR4 3200 DRAM + RTX 3070 or RTX 3080. (have to wait for Zen3, not sure the exact shipping day, Oct. or Nov. but can’t wait so long…)
    I have no idea about CPU resources and DRAM usages needed for daily code development debuging and compiling. if 3700X is not so slow. I can use 3700X for a short time, and replace it with a Zen3 CPU next year. or got a 3900X and upgrade it two years later.

It’s not about the number of cores but the RAM controller that is Quad-Channel instead of Dual-Channel on AMD Threadripper and Intel LGA2066 CPUs which absolutely makes a difference on software like 3D engines as UE4.
You can go with Option 1 of your list and get a RTX 3070 instead of RTX 3080 , use the money for 64GB RAM. Unless you absolutely need maximum RayTracing performance there is not much difference development wise between using a RTX 3070 or a RTX 3080. A RTX 3060 would be more than enough as well.

@DarkS474 , thank you for you advice! Finally i got the following:
Ryzen3700X+Asus TUF B550M+Netac 2T SSD(3.5GB/s reading)+kingston 1T SDD(500MB/s reading)+32G 3200 DRAM+RTX 2060…
It takes about 33 minutes to compile unreal engine source code from the beginning. not so fast, but enough for me to use, and also much more faster than my labtop. But when i import large scenes from QUIXEL, seems DRAM is limited. however, i can work with unreal now.